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Background There are controversial reports on QT interval response to ganglionic plexi ablation that are selectively targeted during cardioneuroablation (CNA) or occurs as collateral lesion during left atrial ablation procedures. Both shortening or prolongation of the heart-rate corrected QT interval (QTc) with therapeutic or safety implications were described. Purpose In this retrospective study, we investigated longitudinal changes of QTc after CNA. Methods The study included 108 patients (age: 39±12 years, 60% males) who underwent biatrial cardioneuroablation (radiofrequency time: 15.5±6.7 min) for symptomatic functional bradyarrhythmias. Surface ECG examinations were performed on the day before the CNA (N=108), 1 hour after the CNA (N=106), on the 1st post-ablation day (N=50), at the 3-month (N=99), and 1-year (N=63) follow-up visits. Automated measurements of QT interval were employed for the analysis. Four formulas (Bazett, Framingham, Fridericia, and Hodges) were used for the correction of QT interval to instant heart rate. Results QTc significantly prolonged immediately after the CNA with rapid return to baseline values (Figure and Table). This was particularly valid for QT correction by Framingham formula (and similarly for Fridericia and Hodges formulas). The QTc by Bazett formula, which is known to overestimate QT at higher heart rates, returned to baseline more slowly and incompletely. Several mechanisms may contribute to observed QTc dynamics: (1) direct effect of autonomic denervation with recovery phenomenon; (2) QT hysteresis with an extremely long time constant; or (3) artifact due to suboptimum QT correction to a substantial change of heart rate. Conclusions The study suggests that CNA produces acute prolongation of QTc interval with rapid decay and virtual normalization in 3 months. CNA in otherwise healthy subjects is not likely associated with substantial long-term risk of long-QT-associated arrhythmias. In the same way, we cannot confirm earlier observations of clinically significant QTc shortening effect of ganglionated plexi ablation. Funding Acknowledgement Type of funding sources: None. Figure 1Table 1

Background In patients with atrial fibrillation (AF), pulmonary vein isolation (PVI) by radiofrequency (RF) energy is associated with a significant change of cardiac autonomic regulations due to collateral ganglionic plexi ablation. Pulse-field (PF) ablation energy presumably spares neural tissue. Purpose We compared the effect of PVI by PF and RF energy on cardiac autonomic function. Methods A study enrolled 23 patients who underwent PVI in general anaesthesia. In 12 patients, a novel lattice-tip catheter and PF energy were used for ablation while 11 patients were ablated using a conventional irrigated-tip catheter and RF energy. The response of the sinus node (SAN) and atrioventricular node (AVN) to extracardiac high-frequency vagal stimulation (ECVS) was tested before and after PVI (via right internal jugular vein; stimulation frequency of 50 Hz; pulse width of 0.05 ms; output of 1 V/kg ( Results At baseline, physiological massive response to ECVS (sinus arrest and/or AV block) was demonstrated in the majority of patients. After PVI, complete loss of autonomic response of the SAN in 11/11 (100%) and 3/12 (25%) patients (p=0.003), and the AVN in 9/11 (82%) and 3/12 (25%) patients (p=0.01) was observed in RF and PF groups, respectively. The figure shows the maximum duration of the pause in sinus rhythm (maximum P-P interval) and AVN block (maximum R-R interval during atrial pacing) induced by ECVS after PVI. Conclusion Cardiac vagal response is preserved in a considerable proportion of AF patients after PF ablation which is in contrast with a significantly stronger effect of RF energy. This may influence the clinical outcome of AF ablation procedures. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Institute for Clinical and Experimental Medicine, Prague

Background Nonischaemic cardiomyopathy (NICM) represents a heterogenic disorder with a variable arrhythmogenic substrate. Its location is often epicardial and catheter ablation in this location proved to be an effective therapeutic modality in NICM patients with recurrent ventricular tachycardias (VTs). Purpose To determine the impact of the type of genetic mutation on the long-term outcome of endo-epicardial ablation in patients with NICM. Methods We investigated 82 patients (age 47±15 years, 10 women) with NICM who underwent endo-epicardial ablation for frequent VTs. Of them, 59% had a history of failed endocardial ablation. Patients had a left ventricular ejection fraction of 44±14% and all were implanted with cardioverter-defibrillator. One hundred candidate genes were examined using the new generation sequencing technique. Results Mutation in genes coding desmosomal complex (genes: PKP2, DSC, DSP, and DSG) was found in 30% of patients (“desmosomal” group). In 23% of patients, other gene mutations (genes: LMNA/C, MYH7, DES, TTN, RYR2, TPM1, MYPN, FLNC, and SCN5A) were detected (“non-desmosomal” group). In 46% of subjects no pathogenic mutation could be identified (“none” group). During a mean follow up of 34±33 months, patients in the “non-desmosomal” group were at significantly higher risk of VT recurrence and death/heart transplant compared to patients in the “desmosomal” group (Figure 1). Conclusion Potentially pathogenic mutation can be detected in about half of patients with NICM undergoing endo-epicardial VT ablation. Most commonly, mutations can be found in genes coding desmosomal complex and the endo-epicardial ablation is then associated with a satisfactory low VT recurrence rate and excellent survival in the long-term. On the other hand, patients with a mutation in non-desmosomal genes have poor outcomes despite endo-epicardial ablation. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Supported by Ministry of Health of the Czech Republic, grant nr. NV18-02-00237 Figure 1

Background We evaluated the differences in the anatomy of the cavotricuspid isthmus (CTI) by assessing image loops provided by intracardiac echocardiography (ICE) in patients who underwent ablation for atrial flutter and/or atrial fibrillation. Purpose CTI is an essential component of the reentrant circle in isthmus–dependent atrial flutter (CTI-AFL) and a target for catheter ablation. In some patients, CTI anatomy may be responsible for a difficult procedure. The aim of this study is to describe in details the anatomical variants of this structure. Methods We included a group of 138 patients, who underwent cardiac ablation for atrial flutter and/or atrial fibrillation between August 2020 and January 2021. Intracardiac echocardiography was employed during the intervention to evaluate the morphology of CTI. Analysis was focused on size, shape, presence of sub-eustachian pouch (excavation more than 5 mm) or presence of prominent Eustachian ridge (ER, embryologic remnant of the valve of the IVC) and mobility of the structure. Results The length of CTI measured during ventricular systole averaged at 38,4mm (min 22,5mm, max 60mm). The most frequent pattern was a flat CTI without sub-eustachian excavation or with excavation less than 5mm (71 patients; 51.4%). A pouch (excavation more than 5mm) was observed in 41 pts (29.7%), where the deepest pouch reached 10,5mm. Prominent ER was present in 58 pts (42%). The remaining 26 of CTIs (18.8%) were classified in the “unclassifiable” category with deviations from common anatomic variants - substantial convexity, pronounced trabeculation of isthmus or double pouch. We observed 14 CTIs (10.1%), where the structure was partially or in full extent detached from the diaphragm, sliding during cardiac contractions. In addition to the described morphology, Chiari's network was observed in 18 pts (13%). In reference to mobility, 53 pts (38.4%) presented with hypermobile CTI with a difference in size of more than 1/3 between the diastole and systole. Moreover, we looked into differences of CTI related to BMI, left atrial volume index (LAVi) and ejection fraction of the left ventricle. A positive correlation was found between LVEF and mobility of CTI. Hypermobile CTI was present in 42.2% of pts with normal LVEF compared to only 18.9% of pts with reduced EF (EF less than 50%). Similar results were observed in pts with non-dilated LA, where hypermobile CTI was present in 51.9% of pts compared to only 35.1% of pts with dilated LA with LAVi >28 ml/m2 (see table below). Conclusions We observed a substantial differences in the anatomy of the CTI, which could play an important role in catheter ablation of this structure. Besides the prominent ER, significant sub-eustachian pouch and hypermobility appear to be variants predisposing to difficult ablation. Funding Acknowledgement Type of funding sources: None. CTI variants related to EFLV, BMI, LAViCTI detached from the diaphragm

Funding Acknowledgements Type of funding sources: None. Background Radiofrequency catheter ablation of superior paraseptal ganglionic plexus is an important step to eliminate the vagal modulation of sinus node for the treatment of neurally-mediated syncope. The reasonable effect can be achieved by targeting this plexus from the endocardial aspect of both right (RA) and left (LA) atria. Purpose We investigated the efficacy of RA and LA ablation in terms of sinus nodal denervation. Methods The study included 24 patients (age: 42 ± 13 years, 50% males) who underwent cardioneuroablation for recurrent cardioinhibitory syncope in general anesthesia. Right atrial semicircular lesion at the posteroseptal quadrant of superior vena cava ostium was composed of 5-6 equidistantly distributed ablation sites (30 W, 30 s, 20 ml/min). Left atrial lesion of comparable size was placed strictly contralaterally across the interatrial septum in the anterior vestibulum of a right superior pulmonary vein. Patients were randomly (1:1) assigned to RA-to-LA or LA-to-RA ablation. Sinus rate and the response to extracardiac right vagal nerve high-frequency stimulation (50 Hz, 0.05 ms, 1 V/kg [ Results Study protocol ablations overall resulted in sinus acceleration (81 ± 13 vs. 59 ± 12 bpm, P Conclusions Neither RA nor LA approach is preferable for targeting the superior paraseptal ganglionic plexus. Both ablation clusters convey complementary and, in part, mutually independent effects. Biatrial cardioneuroablation seems essential for efficacious sinus nodal denervation. Abstract Figure.

Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): IKEM Background Pulmonary vein isolation (PVI) is an established treatment modality for patients with atrial fibrillation (AF). PVI performed by radiofrequency (RF) energy results in parasympathetic denervation of the heart by collateral ganglionic plexi ablation. Pulse field (PF) is a novel nonthermal energy source for PVI that selectively ablates atrial myocardium while preserving cardiac autonomic nerves, which may affect the outcome after PVI. Purpose The study compared the effect of PVI between RF and PF ablation on cardiac autonomic function and a short-term AF recurrence rate. The resting heart rate (HR) was evaluated as a simple index of sinus nodal parasympathetic innervation. Methods We investigated 45 patients (aged 64 ± 7 years, 4 women) who underwent PVI by novel three-dimensional electroanatomical mapping/ablation system (lattice electrode ablation system). PVI was performed by either high-energy RF (n = 21) or PF (n = 24) energy using the identical ablation catheter. Resting HR assessed by standard ECG was recorded the day before the procedure and at the 3-month visit. Arrhythmia recurrences were analysed by 24-Holter at the 3-month visit. Results All PVs were acutely isolated in all patients. The HR data are shown in the Table. The baseline HR did not differ between both groups. A significant increase in HR was observed only in the RF ablation subgroup. The between-group difference remained significant even after adjustment for age, gender, and baseline HR. There was no difference in arrhythmia recurrences at the 3-month visit between study groups. Conclusions Parasympathetic denervation effects on HR after the PF ablation are virtually absent. Comparable AF recurrence rate at 3-month visit after RF and PF ablation suggests that preservation of autonomic innervation has no impact on AF recurrence during short-term follow-up. Table RF PVI (n = 21) PF PVI (n = 24) P Baseline HR (bpm) 60.0 ± 7.1 63.8 ± 9.4 n.s. HR change - 3-month visit (bpm) 14.4 ± 6.9 0.3 ± 8.6 P

Background Intracardiac echocardiography (ICE) is routinely used for guiding cardiac ablation procedures. However, the potential of ICE for measurement of renal artery (RA) blood flow (RABF) has not been fully exploited. Aims To investigate the feasibility of ICE for the assessment of RABF and to evaluate its reproducibility in humans. Methods The study included 15 patients undergoing catheter ablation of atrial fibrillation guided by ICE (age: 61±14 years, body mass index: 30±5 kg/m2, left ventricular ejection fraction: 57±6%, serum creatinine: 80±29 μmol/l). During sinus rhythm, the ICE probe was withdrawn from the right atrium to the inferior vena cava until the right RA with its ostium became visible. Blood flow in the RA was visualized by colour flow mapping. The RA diameter was measured at 10 mm from the ostium. RABF at this location was measured by pulse wave Doppler. Velocity-time integral (VTI) was delineated manually and averaged over five consecutive beats. RABF was calculated by the formula: RABF = (RA radius)2 x π x VTI x heart rate. To assess reproducibility of the method, the ICE probe was repositioned in the right atrium and the measurement of RABF was repeated by the same operator. Results The right RA was visualized in all 15 patients. No procedure-related clinical complications occurred. The mean RA radius was 2.5±0.4 mm. In all cases, the angle of incidence during the measurement of VTI was Conclusions This study demonstrated that measurement of RABF by ICE is feasible and has reasonable intra-observer reproducibility. The method can be used to study RABF during various interventions and hemodynamic conditions. Figure 1. Intra-individual reproducibility Funding Acknowledgement Type of funding source: None

Background Radiofrequency catheter ablation of inferior atrial ganglionic plexi frequently results in vagal denervation of the atrioventricular (AV) node. The effective sites are, however, considerably variable. Purpose We prospectively sought the left atrial (LA) ablation site with the maximum effect on AV nodal modulation. Methods The study included 16 patients (age: 46±14 years, 56% males) who underwent cardioneuroablation for recurrent reflex cardioinhibitory syncope in general anesthesia. After targeting the superior paraseptal ganglionic plexi and achieving the denervation of the sinus node, study ablations were performed at the bottom of the LA to accomplish the AV nodal denervation (Figure). Five equidistantly distributed ablation lesions (30W / 30s / 20ml/min) were created on the virtual line connecting inferior ostium of right inferior pulmonary vein (RIPV) and inferior mitral annulus (MA). Lesions were centered symmetrically relative to the posterior mid-left-atrial line. They were numbered in ascending order from #1 (more septal, closer to the RIPV) to #5 (more lateral, closer to the MA). Patients were randomly (1:1) assigned to mutually opposite direction of ablation (from site #1 to #5 or from site #5 to #1). The response of heart rhythm to extracardiac vagal nerve high-frequency stimulation (50Hz/0.05ms/1V/kg [ Results Study protocol ablations overall resulted in elimination or attenuation of inducible AV block (maximum R-R interval: 2.9±2.8 vs. 5.2±2.4s, P Conclusion Ablation of perimitral region of the inferior LA conveyed the maximum effect in terms of AV nodal denervation. Funding Acknowledgement Type of funding source: None

Background Ablation of superior paraseptal ganglionic plexi is invariantly associated with the acceleration of sinus rhythm. This is considered a favourable sign during cardioneuroablation for the treatment of recurrent neurally-mediated cardioinhibitory syncope or symptomatic sinus bradycardia. Purpose In this retrospective study, we investigated whether the magnitude of sinus rhythm acceleration corresponds with directly assessed sinus nodal parasympathetic denervation. Methods The study included 48 patients (age: 39 ± 13 years, 58% males) who underwent cardioneuroablation in general anaesthesia. The procedural endpoint was non-responsiveness (i.e. loss of original cardioinhibitory response) of the sinus node to extracardiac high-frequency stimulation of the vagal nerve. The magnitude of sinus rhythm acceleration was compared between patients who reached or did not reach this endpoint. Results All patients had positive atropine test (baseline heart rate: 65 ± 14 bpm; post-atropine: 109 ± 22 bpm). Complete sinus nodal denervation as assessed by vagal nerve stimulation was achieved in 44/48 (92%) patients. Intraprocedurally, heart rate accelerated from 54 ± 11 to 85 ± 14 bpm (difference: 31 ± 10; median 29; interquartile range: 24–40; total range: 13–61 bpm). This change did not correlate with age and was not related to pre-procedural post-atropine sinus rhythm acceleration. There was no difference in heart rate acceleration between the patient with and without sinus nodal denervation (Figure). Conclusions Sinus rhythm acceleration is not reliable endpoint for cardioneuroablation. Guidance by extracardiac vagal nerve stimulation may help to tailor the procedures to increase the clinical success rate and, at the same time, to avoid patient overtreatment. Abstract Figure.

ObjectivesThe association between obesity and atrial fibrillation (AF) is well-established. We aimed to evaluate the impact of index body mass index (BMI) on AF recurrence at 12 months following catheter ablation using propensity-weighted analysis. In addition, periprocedural complications and fluoroscopy details were examined to assess overall safety in relationship to increasing BMI ranges.MethodsBaseline, periprocedural and follow-up data were collected on consecutive patients scheduled for AF ablation. There were no specific exclusion criteria. Patients were categorised according to baseline BMI in order to assess the outcomes for each category.ResultsAmong 3333 patients, 728 (21.8%) were classified as normal (BMI 2), 1537 (46.1%) as overweight (BMI 25.5–29.0 kg/m2) and 1068 (32.0%) as obese (BMI ≥30.0 kg/m2). Procedural duration and radiation dose were higher for overweight and obese patients compared with those with a normal BMI (p=0.002 and p2led to a 1.2-fold increased likelihood of experiencing recurrent AF at 12-months follow-up as compared with overweight patients (HR 1.223; 95% CI 1.047 to 1.429; p=0.011), while no significant correlation was found between overweight and normal BMI groups (HR 0.954; 95% CI 0.798 to 1.140; p=0.605) and obese versus normal BMI (HR 1.16; 95% CI 0.965 to 1.412; p=0.112).ConclusionsPatients with a baseline BMI ≥30 kg/m2have a higher recurrence rate of AF following catheter ablation and therefore lifestyle modification to target obesity preprocedure should be considered in these patients.

Aims Complications of catheter ablation for atrial fibrillation (AF) are frequently related to vascular access. We hypothesized that ultrasound-guided (USG) venipuncture may facilitate the procedure and reduce complication rates. Methods and results We conducted a multicentre, randomized trial in patients undergoing catheter ablation for AF on uninterrupted anticoagulation therapy. The study enrolled consecutive 320 patients (age: 63 ± 8 years; male: 62%) and were randomized to USG or conventional venipuncture in 1:1 fashion. It was prematurely terminated due to substantially lower-than-expected complication rates, which doubled the population size needed to maintain statistical power. While the complication rates did not differ between two study arms (0.6% vs. 1.9%, P = 0.62), intra-procedural outcome measures were in favour of the USG approach (puncture time, 288 vs. 369 s, P

AimThe purpose of this study was to compare sex differences of atrial fibrillation (AF) catheter ablation (CA) and to analyse the opportunities for improved outcomes.Methods and resultsAll data were collected from the Atrial Fibrillation Ablation Long-Term registry, a prospective, multinational study conducted by the ESC-EORP European Heart Rhythm Association (EHRA) under the EURObservational Research Programme (ESC-EORP). A total of 104 centres in 27 European countries participated. Of 3593 included patients, 1146 (31.9%) were female. Female patients were older (61.0 vs. 56.4 years; P ConclusionFemales underwent CA procedures for AF less frequently than males throughout Europe, despite more recurrent symptoms. With the same success rate, severe acute complications remained considerable in females, especially in less experienced centres.

Background Cardioneuroablation by targeting of atrial ganglionic plexi (GP) has been proposed as a new therapeutic option in selected patients with reflex syncope. Contribution of individual GPs to cardiac autonomic regulations is not fully established. Purpose Because consistent vagal responses have been observed during left superior pulmonary vein isolation in patients undergoing ablation for atrial fibrillation, we investigated whether standalone ablation of the superior left GP modifies the vagal input into the sinoatrial (SAN) and atrioventricular node (AVN). Methods Study hypothesis was investigated in otherwise healthy patients undergoing cardioneuroablation for symptomatic bradyarrhythmias. All had preprocedural atropine test suggesting functional disorder. Anatomically-navigated (CARTO-3) radiofrequency (RF) ablation (25–30 W/30 s/20 ml/min) at empirical GP sites was performed in general anaesthesia. Extracardiac high-frequency vagal nerve stimulation (25–60 V/30–50 Hz/0.05–0.1 ms) via right jugular vein was performed at baseline, after initial superior left GP ablation, and after the ablation of remaining septal and inferior GPs. High-frequency vagal nerve stimulation was always done in both sinus rhythm and atrial pacing. The elimination of all stimulation-induced vagal responses was the endpoint of the procedure. Results A study included 8 patients (34±8 years; 5 males). Six of them had recurrent syncope with cardioinhibitory response at the SAN (n=4), AVN (n=1) or both nodes (n=1); and 2 patients had symptomatic sinus bradycardia. At baseline, high-frequency vagal nerve stimulation induced long episodes of sinus arrest and advanced AV block in all patients. Cluster ablation at the superior left GP (RF time: 192±28 s) did not change the sinus rate (59±14 vs 60±15, NS), PQ interval (174±37 vs 173±37, NS), and did not induce any tangible change in SAN/AVN response to high-frequency vagal nerve stimulation. Subsequently, anterior right GP was targeted from the aspect of right atrium (n=7), from the anterior antrum of right pulmonary veins (n=6), and inferior GPs were targeted from the aspect of left atrium (n=7). This lesion set finally resulted in complete non-responsiveness of SAN and AVN to high-frequency vagal nerve stimulation in all patients. Ablation procedure overall (duration: 172±15 min; RF time: 988±306 s; radiation dose: 70±34 μGy·m2) led to sinus rate acceleration by a median of 29 (IQR: 18–38) bpm, increase of Wenckebach point by 21 (IQR: 9–28) bpm, and shortening of AVN effective refractory period by 40 (IQR: 15–73) ms. Conclusions Cardioneuroablation guided by extracardiac high-frequency vagal nerve stimulation can achieve complete denervation of SAN and AVN by ablation of postero(para)septal and inferior GPs only. Ablation of the superior left GP appears unnecessary and can be eliminated from the lesion set design.

Background Catheter ablation of ventricular tachycardia (VT) in patients with structural heart disease (SHD) is effective in prevention of arrhythmia recurrences. However, endocardial ablation may be challenging in the presence of organized left ventricular (LV) endocavitary thrombus. Our goal was to analyze the results of VT ablation in patients with identified old thrombus. Methods and results We reviewed clinical and procedural data of 344 consecutive patients who underwent VT ablation for SHD. Old endocavitary thrombus was identified in four patients by preprocedural transthoracic echocardiography (TTE) and in four more patients by intracardiac echocardiography (ICE). All together, the case series of eight patients with detectable thrombus is reported. All patients (one woman, age: 67 ± 7 years) had postinfarction aneurysm (20 ± 8 years after the index myocardial infarction) and the thrombus was well organized without mobile structures. Arrhythmogenic substrate could not be obviously targeted beneath the base of thrombus; however, catheter ablation was successfully performed in the close vicinity. A total of 2.4 ± 1.2 procedures were necessary to abolish VT recurrences. Epicardial ablation was performed in three of eight (38%) patients as a second elective procedure. No procedural or periprocedural complications were observed. During the follow-up of 14 ± 15 months, two patients (25%) had sporadic VT recurrences. Conclusions ICE seems to be more sensitive for the detection of LV thrombi compared to TTE and is helpful in real-time navigation of mapping/ablation catheter. Besides potential thromboembolic risk, large thrombus may prevent accessibility to the "critical" portion of arrhythmia circuit and epicardial ablation is required in selected cases.

VT Ablation in Patients With Preserved LV FunctionIntroduction Patients with coronary artery disease (CAD), relatively preserved left ventricular ejection fraction (LVEF), and hemodynamically tolerated ventricular tachycardia (VT) may benefit from catheter ablation as the first-line treatment. Our aim was to analyze the long-term results of VT ablation in this population. Methods and Results Thirty-one patients (1 woman, mean age 67 ± 10 years) with CAD, tolerated VT, and LVEF ≥40% underwent catheter ablation as the first-line treatment of the arrhythmia. Catheter ablation was performed in order to abolish all inducible VTs. An ICD was implanted if sustained VT of any morphology remained inducible after the procedure. The mean LVEF was 48 ± 6% and the mean VT cycle length reached 348 ± 70 milliseconds in the study cohort. Clinical and all inducible VTs were abolished in 90% (28/31) and 58% (18/31) of the patients, respectively. An ICD was subsequently implanted in 42% of cases. Over a mean follow-up of 3.8 ± 2.9 years, 42% (13/31) patients died. Survival of the patients with or without the ICD was not significantly different (P = 0.47). VT recurrence was observed in 11% (2/18) of patients who had complete elimination of all inducible VTs. No sudden death occurred in patients without the ICD. Conclusions Catheter ablation of VT as the first-line treatment in patients with CAD and relatively preserved LVEF is a viable strategy. It may prevent implantation of the ICD in a considerable proportion of patients. Abolition of all inducible VTs confers low VT recurrence rate over a long-term follow-up.

Aims A challenge of pulmonary vein isolation (PVI) in catheter ablation for paroxysmal atrial fibrillation (PAF) is electrical reconnection of the PV. EFFICAS I showed correlation between contact force (CF) parameters and PV durable isolation but no prospective evaluation was made. EFFICAS II was a multicentre study to prospectively assess the impact of CF guidance for an effective reduction of PVI gaps. Methods and results Pulmonary vein isolation using a radiofrequency (RF) ablation catheter with an integrated force sensor (TactiCath™) was performed in patients with PAF. Operators were provided EFFICAS I-based CF guidelines [target 20 g, range 10–30 g, minimum 400 g s force-time integral (FTI)]. Conduction gaps were assessed by remapping of PVs after 3 months, and gap rate was compared with EFFICAS I outcome. At follow up, 24 patients had 85% of PVs remaining isolated, compared with 72% in EFFICAS I ( P = 0.037) in which CF guidelines were not used. The remaining 15% of gaps correlated to the number of catheter moves at creating the PVI line, quantified as Continuity Index. For PV lines with contiguous lesions and low catheter moves, durable isolation was 81% in EFFICAS I and 98% in EFFICAS II ( P = 0.005). At index procedure, the number of lesions was reduced by 15% in EFFICAS II vs. EFFICAS I. Conclusion The use of CF with the above guidelines and contiguous deployment of RF lesions in EFFICAS II study resulted in more durable PVI in catheter ablation of PAF. [10.1093/europace/euv131][1] [1]: /lookup/doi/10.1093/europace/euv131

Introduction Frequent ventricular premature complexes (VPCs) may cause symptoms and/or lead to deterioration of LV systolic function. Although frequent VPCs may be abolished by catheter ablation, it may be challenging in case of their origin from the LV papillary muscles (PMs). Our collaborative study aimed to analyze in detail the site of origin and the outcome of ablation. Methods Consecutive 34 patients (males: 68%; aged 62±12 years; LV ejection fraction: 50±9%) undergoing catheter ablation of VPCs originating from PMs were included. All procedures were guided by intracardiac echocardiography. Results The size and shape of PMs were highly variable. The length of anterolateral and posteromedial PM was 23±4 mm and 28±7 mm, respectively. In about one-third of patients, the PM was formed by two distinctly separate heads. The ectopic foci were located on anterolateral, posteromedial or both PM in 35%, 56% and 9% of cases, respectively. Their location was found within the distal, mid or proximal (basal) third of PM in the 67%, 19% and 14%, respectively. A total of 86% of PM foci were acutely abolished and long-term success was achieved in 65% of patients. Absence of VPCs of other morphologies and a high burden of ectopic activity before ablation were associated with favorable clinical outcome. Conclusion VPCs originate predominantly from the distal portion of the PM. This knowledge may facilitate the mapping in patients with infrequent ectopic beats. Intracardiac echocardiography is of crucial importance for navigation of the ablation catheter and for assessment of its stability at PM target sites. This article is protected by copyright. All rights reserved

Background— Catheter ablation has become an established treatment modality for a broad spectrum of ventricular tachycardias (VTs). We analyzed incidence and predictors of major complications of VT ablation procedures in a high-volume expert center. Methods and Results— We evaluated 548 consecutive patients who underwent 722 ablation procedures, 473 (65.5%) for structural heart disease VT in the period 2006 to 2012. There were 45 (6.2%) major complications observed in 44 patients. Access site vascular complications were the most frequent (3.6%). Three patients (0.4%) had cardiac tamponade/hemopericardium, and 5 patients (0.7%) had a thromboembolic event. No procedural deaths occurred. Procedures for structural heart disease VT versus idiopathic VT had a significantly higher complication rate (8.0% versus 2.8%; P =0.006). Similarly, patients with electrical storm (10.1% versus 5.3%; P =0.04) and nonelective procedures (8.4% versus 3.5%; P =0.007) were at higher risk of complications. On multivariate analysis, age >70 years ( P =0.01), serum creatinine >115 μmol/L ( P =0.0003), and individual operator ( P =0.0001) were the only independent predictors of complications. Overall 30-day mortality in the structural heart disease VT group reached 5.0% (patients) and 3.6% (procedures). Death was associated with early recurrence of VT/ventricular fibrillation ( P =0.003) and ablation for electrical storm ( P =0.02). Conclusions— Complication rates for VT ablation are significantly lower in idiopathic VT or in elective procedures. Independent predictors of complications include age, renal insufficiency, and individual operator. Postprocedural mortality is predicted by early recurrence of VT/ventricular fibrillation and ablation for electrical storm.

Background— During radiofrequency ablation, high electrode-tissue contact force (CF) is associated with increased risk of steam pop and perforation. The purpose of this study, in patients undergoing ablation of paroxysmal atrial fibrillation, was to: (1) identify factors producing high CF during left atrial (LA) and pulmonary vein mapping; (2) determine the ability of atrial potential amplitude and impedance to predict CF; and (3) explore the feasibility of controlling radiofrequency power based on CF. Methods and Results— A high-density map of LA/pulmonary veins (median 328 sites) was obtained in 18 patients undergoing atrial fibrillation ablation using a 7.5-Fr irrigated mapping/ablation catheter to measure CF. Average CF was displayed on the 3D map. For 5682 mapped sites, CF ranged 1–144 g (median 8.2 g). High CF (≥35 g) was observed at only 118/5682 (2%) sites, clustering in 6 LA regions. The most common high CF site (48/113 sites in 17/18 patients) was located at the anterior/rightward LA roof, directly beneath the ascending aorta (confirmed by merging the CT image and map). Poor relationship between CF and either unipolar amplitude, bipolar amplitude, or impedance was observed. During ablation, radiofrequency power was modulated based on CF. All pulmonary veins were isolated without steam pop, impedance rise, or pericardial effusion. Conclusions— High CF often occurs at anterior/rightward roof, where the ascending aorta provides resistance to the LA. Atrial potential amplitude and impedance are poor predictors of CF. Controlling radiofrequency power based on CF seems to prevent steam pop and impedance rise without loss of lesion effectiveness.

Aims To investigate predictors of long-term outcomes after catheter ablation (CA) for ventricular tachycardia (VT) and the impact of electrical storm (ES) prior to index ablation procedures. Methods We studied consecutive patients with structural heart disease and VT (n = 328; age: 63±12 years; 88% males; 72% ischaemic cardiomyopathy; LVEF: 32±12%) who had undergone CA. According to presenting arrhythmia at baseline, they were divided into ES (n = 93, 28%) and non-ES groups. Clinical predictors of all-cause mortality were investigated and a clinically useful risk score (SCORE) was constructed. Results During a median follow-up of 927 days (IQR: 564-1626), 67% vs. 60% of patients (p = 0.05) experienced VT recurrence in the ES vs. the non-ES group, respectively; and 41% vs. 32% patients died (p = 0.02), respectively. Five factors were independently associated with mortality: age >70 years (hazard ratio (HR): 1.6, 95% confidence interval (CI): 1.1-2.4, p = 0.01), NYHA class ≥3 (HR: 1.9, 95% CI: 1.2-2.9, p = 0.005), a serum creatinine level >1.3 mg/dL (HR: 1.6, 95% CI: 1.1-2.3, p = 0.02), LVEF ≤25% (HR: 2.4, 95% CI: 1.6-3.5, p = 0.00004), and amiodarone therapy (HR: 1.5, 95% CI: 1.0-2.2, p = 0.03). A risk SCORE ranging from 0-4 (1 point for either high-risk age, NYHA, creatinine, or LVEF) correlated with mortality. ES during index ablation independently predicted mortality only in patients with a SCORE ≤1. Conclusions Advanced LV dysfunction, older age, higher NYHA class, renal dysfunction, and amiodarone therapy, but not ES, were predictors of poor outcomes after CA for VT in the total population. However, ES did predict mortality in a low-risk sub-group of patients.

Aims Catheter ablation (CA) for atrial fibrillation (AF) is a complex procedure that is associated with higher risk of complications. This study aimed at exploring the complication rate and corresponding risk factors in a high-volume centre with routine use of intracardiac echocardiography (ICE). Methods and results In total 1192 consecutive AF ablation procedures (100% ICE-guided; 96.4% 3D-navigated; point-by-point radiofrequency ablation with open-irrigated tip catheter; 22.4% robotic navigation; 25.4% repeated ablation) were performed in 959 patients (aged 58 ± 9 years; 70.8% males; 35.9% persistent AF) between March 2006 and December 2010. Ablation endpoint in paroxysmal AF was complete electrical pulmonary vein isolation (PVI). Complex ablation was defined as PVI plus stepwise strategy for left atrial substrate ablation (43.5%) in persistent AF. Forty major complications (3.3%) during the procedure or within the 3 month follow-up were observed. No death or atrioesophageal fistula occurred. Three patients (0.25%) had cardiac tamponade/hemopericardium and five patients (0.42%) had cerebrovascular embolic event. Vascular injury was the most frequent (2.3%) complication. Low body weight was the only significant risk factor with 0.8% increase of complication rate per 10 kg of body weight decrease ( P = 0.013). A trend for increase in complication rate was also observed for advanced age, female gender, and complex procedure. Conclusion Atrial fibrillation ablation procedures guided by ICE in a high-volume centre are associated with low rate of serious complications. The composite risk score consisting of body weight, age, gender, and complexity of procedure predicted complications.

Frequent episodes of polymorphic ventricular tachycardias/ventricular fibrillation (VT/VF) in patients with coronary artery disease can be triggered by monomorphic ventricular premature beats (VPBs) and thus, amenable to catheter ablation. The goal of this study was to review single-center experience in catheter ablation of electrical storm caused by focally triggered polymorphic VT/VF. Catheter ablation of electrical storm due to focally triggered polymorphic VT/VF was performed in nine patients (mean age, 62 ± 7 years; two females). All patients had previous myocardial infarction (interval of 3 days to 171 months). Mean left ventricular ejection fraction was 27 ± 6%. All patients presented with repeated runs of polymorphic VT/VF triggered by monomorphic VPBs. Based on mapping data, the ectopic beats originated from scar border zone on interventricular septum (n = 5), inferior wall (n = 3), and lateral wall (n = 1). Catheter ablation was performed to abolish the triggering ectopy and to modify the arrhythmogenic substrate by linear lesions within the infarct border zone. The ablation procedure was acutely successful in eight out of nine patients. During the follow-up of 13 ± 7 months, two patients died due to progressive heart failure. One patient had late recurrence of electrical storm due to ectopic beats of different morphology and was successfully reablated. Electrical storm due to focally triggered polymorphic VT/VF may occur either in subacute phase of myocardial infarction or substantially later after index event. Catheter ablation of ectopic beats triggering these arrhythmias can successfully abolish electrical storm and become a life-saving procedure.

INTRODUCTION Pulmonary venous antra isolation (PVAI) is the cornerstone of catheter ablation procedure for drug refractory paroxysmal atrial fibrillation (AF). However, the procedure is technically challenging. Robotic navigation has a potential to expedite and facilitate the procedure. METHODS A robotic catheter control system was used for remote navigation-supported PVAI in 22 patients (mean age = 55 +/- 9 years, 16 males, study group). An irrigated-tip catheter with estimate of catheter force on the tissue was used. This was compared in nonrandomized fashion with conventional hand-controlled catheter ablation in 16 patients (mean age = 55 +/- 9 years, 13 males, control group). The procedures were performed under guidance of Ensite NavX navigation system (St. Jude Medical, St. Paul, MN, USA) and intracardiac echocardiography. RESULTS Robotic navigation was associated with significantly shorter overall duration of radiofrequency delivery (1,641 +/- 609 vs 2,188 +/- 865 seconds, P < 0.01), shorter total procedural time (207 +/- 29 vs 250 +/- 62 minutes, P = 0.007), fluoroscopy exposure (15 +/- 5 vs 27 +/- 9 minutes, P < 0.001), and lower radiation dose (1,119 +/- 596 vs 3,048 +/- 2,029 mGy/m(2), P < 0.001). No complication was observed in either the study or the control group. During the 5 +/- 1 months follow-up in the study group and 9 +/- 3 months in the control group, 91% and 81% of patients, respectively, were AF free. CONCLUSIONS In our early clinical experience, PVAI using a remote robotic catheter navigation was effective, safe, and associated with shorter procedural and fluoroscopic times than conventional PVAI.

Background Mitral isthmus is often targeted as a part of stepwise approach during radiofrequency ablation for persistent atrial ablation. Acute success rate in achieving the mitral isthmus block is only modest, late reconduction rate is relatively high and, consequently, incomplete lesion may be proarrhythmic. We describe the first-in-man experience with successful MI ablation by bipolar RF energy delivery. Case presentation A 64-year-old caucasian man after two previous ablation procedures for drug resistant atrial fibrillation in recent four years, which included pulmonary vein isolation and linear left atrial lesions, was referred for the treatment of recurrent perimitral flutter. Despite the third attempt to create bidirectional block at the mitral isthmus region, we were not even able to stop the arrhythmia by aggressive unipolar radiofrequency ablation both from the left atrium and coronary sinus, because of deeply embedded slow conducting channel probably around the vein of Marshall. Arrhythmia was finally terminated and the block was achieved by bipolar radiofrequency ablation between two irrigated-tip catheters positioned at the left atrial endocardium and contralaterally inside the coronary sinus. Conclusion Bipolar radiofrequency energy delivery can be an option for ablation of perimitral flutter resistant to standard unipolar radiofrequency ablation. This may improve clinical outcome of patients undergoing non-pharmacological treatment for persistent atrial fibrillation. The safety and efficacy of this technique has to be confirmed in future studies.

Introduction: Catheter ablation of atrial fibrillation (AF) requires exact anatomical information about pulmonary venous (PV) ostia. In this study, anatomy of pulmonary veins (PVs) was assessed using three-dimensional (3D) reconstructions of magnetic resonance angiography (MRA). Methods and Results: Contrast-enhanced MRA of the PVs was performed in 40 patients (mean age 53 ± 9 years) with paroxysmal (30 patients) or persistent (10 patients) AF, scheduled for circumferential ablation around PV ostia. PV ostial anatomy and diameters were evaluated from multiplanar reconstructions and compared with 3D reconstructions. Thirty (75%) patients presented with a common left-sided antrum (21 short and 9 long trunk), while additional PVs were found on right side in 23%. PV ostia were oblong in shape (mean diameters 17.0 ± 4.3 vs 10.5 ± 2.5 mm by two-dimensional (2D) measurements, and 20.8 ± 7.6 mm vs 12.9 ± 3.3 mm by 3D reconstruction, in long and short axis, respectively). There was a correlation between measurements obtained from 2D and 3D images, although 3D imaging provided slightly larger diameters. Conclusions: MRA with 3D reconstructions is an important technique for preprocedural assessment of PVs that allows full understanding of their anatomy and size. This information may be important for selection of appropriate tools.

Background Tachycardia-induced tachycardia appears to be a relatively rare condition. In such cases an important question arises whether catheter ablation of one arrhythmia may prevent the occurrence of another. This paper reviews single-centre experience with coincident idiopathic outflow tract ventricular tachycardia (VT) and atrioventricular (AV) nodal reentry tachycardia (AVNRT), and strategy of treatment. Methods and Results Seven of 46 patients (15%) with clinically documented idiopathic outflow tract VT were found to have reproducibly inducible AVNRT at the time of an electrophysiological study. There were two men and five women (mean age 35 9 years, range 20–44) without structural heart disease. During the study, AVNRT spontaneously triggered VT in three cases. Radiofrequency catheter ablation of the slow pathway did not suppress subsequent inducibility of VT in any of them. Successful catheter ablation of VT did not prevent clinical recurrence of AVNRT in one patient, and led to transition of VT into typical AVNRT in another. Conclusion Coincidence of idiopathic outflow tract VT and AVNRT was found in 15% of cases of clinically documented idiopathic VT. Catheter ablation of one arrhythmia substrate did not prevent inducibility or clinical recurrence of the other. These data support the strategy of performing catheter ablation of both arrhythmia substrates during one session.

We present a case of a patient who, after correction of tetralogy of Fallot (TOF), experienced runs of ventricular tachycardia (VT). Mapping of the aortic root showed that the critical component of the reentry was located within the noncoronary cusp. The potential explanations of such an unusual isthmus location may be the presence of myocardial extensions in the aortic root or the close vicinity of the right ventricle (RV) to the noncoronary cusp, since in TOF the aorta overrides the RV. Our case highlights the advantage of using electroanatomic mapping systems together with intracardiac echocardiography in such complex cases.

Aims In patients with severe neurally mediated syncope (NMS), radiofrequency catheter ablation (RFA) of ganglionic plexi (GP) has been proposed as a new therapeutic approach. Cardio-inhibitory response during NMS is usually related to the sinoatrial (SA) and less frequently to atrioventricular (AV) node. Differential effect of GP ablation on SA and AV node is poorly understood. Methods and results We report a case of a 35-year-old female with frequent symptomatic episodes of advanced AV block treated by anatomically guided RFA at empirical sites of GPs. After RFA at the septal portion of the right atrium—superior vena cava junction, heart rate accelerated from 62 to 91 beats/min and PR interval prolonged from 213 to 344 ms. Sustained first-degree AV block allowed to observe directly the effects of subsequent RFA on the AV nodal properties. Subsequent RFA at right- and left-sided aspects of the inter-atrial septum had no further effect on heart rate and PR interval. Ablation at the inferior left GP was critical for restoration of normal AV conduction (final PR interval of 187 ms). No bradycardia episodes were observed by implantable loop recorder during the follow-up of 10 months and the patient was symptomatically improved. Conclusion This is the first clinical case showing the differential effect of GP ablation on SA and AV nodal function, and critical importance of targeting the GP at the postero-inferior left atrium. The successful procedure corroborates clinical utility of ablation treatment instead of pacemaker implantation in selected patients with cardio-inhibitory NMS.

We present a 34-year-old woman with idiopathic ventricular tachycardia that resisted 2 previous attempts for catheter ablation and was successfully ablated in the myocardial extension within the noncoronary aortic cusp.

The visually guided laser ablation (VGLA) catheter is a compliant, variable-diameter balloon that delivers laser energy around the pulmonary vein (PV) ostium under real-time endoscopic visualization. While acute PV isolation has been shown to be feasible, limited data exist regarding the durability of isolation.We sought to determine the durability of PV isolation following ablation using the balloon-based VGLA catheter.The VGLA catheter was evaluated in patients with paroxysmal atrial fibrillation (3 sites, 10 operators). Following transseptal puncture, the VGLA catheter was advanced through a 12-F deflectable sheath and inflated at the target PV ostium. Under endoscopic guidance, the 30° aiming arc was maneuvered around the PV and laser energy was delivered to ablate tissue in a contiguous/overlapping manner. At ∼3 months, all patients returned for a PV remapping procedure.In 56 patients, 202 of 206 PVs (98%) were acutely isolated. At 105 ± 44 (mean ± SD) days, 52 patients returned for PV remapping at which time 162 of 189 PVs (86%) remained isolated and 32 of 52 patients (62%) had all PVs still isolated. On comparing the operators performing10 vs ≥ 10 procedures, the durable PV isolation rate and the percentage of patients with all PVs isolated were found to be 73% vs 89% (P = .011) and 57% vs 66% (P = .746), respectively. After 2 procedures and 12.0 ± 1.9 months of follow-up, the drug-free rate of freedom from atrial fibrillation was 71.2%.In this multicenter, multioperator experience, VGLA resulted in a very high rate of durable PV isolation with a clinical efficacy similar to that of radiofrequency ablation.

Robotic Navigation in Ablation of Paroxysmal AF. Introduction: Remote navigation systems represent a novel strategy for catheter ablation of atrial fibrillation (AF). The goal of this study is to describe a single-center experience with the electromechanical robotic system (Sensei, Hansen Medical) in treatment of patients with paroxysmal AF. Methods: Out of 200 patients who underwent robotically guided ablation for AF between 2007 and 2009 at our institute, 100 patients (29 women, age 56.5 ± 10 years) had paroxysmal AF refractory to antiarrhythmic drugs. Electroanatomic mapping using NavX system (St. Jude Medical) provided anatomical shell for subsequent circumferential ablation with robotic catheter (Artisan) loaded with a 3.5-mm, open-irrigation, cooled-tip ablation catheter. Results: A mean of 69 radiofrequency current applications (duration 2082 ± 812 seconds) were delivered to achieve circumferential electrical isolation of pulmonary venous antra. Total procedural time reached 222 ± 54 minutes. The mean fluoroscopic time was 11.9 ± 7.8 minutes. There were no major procedure-related complications. After a median follow-up of 15 months (range 3-28 months), 63% of the patients were free from any atrial arrhythmias ≥ 30 seconds after the single procedure. Success rate increased to 86% after 1.2 procedures. Multivariate analysis revealed that only predictor of recurrent AF/AT was shorter overall procedural time (207 ± 36 vs 236 ± 64 minutes in patients with and without recurrences, respectively, P = 0.0068). Conclusions: This study demonstrates feasibility and safety of robotic navigation in catheter ablation for paroxysmal AF. Midterm follow-up documents success rate comparable to other technologies and potential for improvement in more extensive ablation along the ridges with thicker myocardium. (J Cardiovasc Electrophysiol, Vol. 22, pp. 534-540 May 2011)

Aims Electrical storm (ES) adversely affects prognosis of patients and may become a life-threatening event. Catheter ablation (CA) has been proposed for the treatment of ES. Our goal was to evaluate the efficacy of CA ablation both in acute and long-term suppression of ES. Methods and results Fifty consecutive patients with coronary artery disease (38), idiopathic dilated cardiomyopathy (5), arrhythmogenic right ventricular cardiomyopathy (6), and/or with combined aetiology (1) underwent CA for ES. Mean left ventricular ejection fraction (LVEF) was 29 ± 11%. All patients underwent electroanatomical mapping, and CA was performed to abolish all inducible ventricular arrhythmias. The ES was suppressed by CA in 84% of patients. During the follow-up of 18 ± 16 months, 24 patients had no recurrences of any ventricular tachycardia (VT; 48%). Repeated procedure was necessary to suppress the recurrent ES in 13 cases (26%). Statistical analysis revealed that low LVEF (22 ± 3 vs. 31 ± 12%; P < 0.001), increased LVend-diastolic diameter (72 ± 9.1vs. 64 ± 8.9 mm; P = 0.0135), and renal insufficiency ( P < 0.001) were the univariate predictors of early mortality or necessity for heart transplantation. Recurrence of ES despite previous CA procedure was associated with a higher risk of death or heart transplant during follow-up ( P < 0.05). Conclusion Catheter ablation is effective in acute suppression of ES and often represents a life-saving therapy. In the long term, it prevents recurrences of any VT in about half of the treated patients.

International audience; AIMS: Little is known about the incidence of paroxysmal atrial tachycardias (PAT) in patients with heart failure (HF). The availability of cardiac resynchronization therapy (CRT) devices with extended diagnostics for AT enables continuous monitoring of PAT episodes. The aim of the study was to assess the incidence over time of PAT in HF patients treated with CRT. METHODS AND RESULTS: Consecutive patients in NYHA functional class III or IV despite optimal drug therapy, QRS duration > or = 130 ms, left ventricular ejection fraction < or = 35%, and left ventricular end-diastolic dimension > or = 55 mm were eligible for enrolment. Patients with permanent or persistent atrial fibrillation (AF) were not included in the study. The first follow-up examination was performed 2 weeks after implantation, to optimize atrial sensing and CRT. Subsequent follow-up examinations were carried out 15 and 28 weeks after implantation, to collect the telemetric data. A total of 173 patients (67 +/- 11 years, M 116) were enrolled. Complete arrhythmia monitoring data were available from 120 patients over a mean follow-up of 183 +/- 23 days. Atrial tachycardia episodes were detected through telemetry in 25 of 120 patients (21%) during at least one follow-up examination. Atrial tachycardia episodes were recorded in 29 and 17% (P = NS) of patients with and without previous history of AF, respectively. CONCLUSION: More than 20% of the overall HF patient population treated with CRT suffer PAT episodes. Paroxysmal atrial tachycardia may interfere with response to CRT. Therefore, telemetric data may be relevant to drive the appropriate therapy in each patient.

Introduction: Image integration is being used in ablation procedures. However, the success of this approach is dependent on the accuracy of the image integration process. This study aims to evaluate the in vivo accuracy and reliability of the integrated image. Methods and Results: One hundred twenty-four patients undergoing radiofrequency (RF) ablation catheter ablation for atrial fibrillation (AF) were recruited for this study from three different centers. Cardiac computerized tomography (CT) was performed in all patients and a 3D image of the left atrium (LA) and pulmonary veins (PVs) was extracted for registration after segmentation using a software program (CartoMerge, Biosense Webster, Inc.). Different landmarks were selected for registration and compared. Surface registration was then done and the impact on integration and the landmarks was evaluated. The best landmark registration was achieved when the posterior points on the pulmonary veins were selected (5.6 ± 3.2). Landmarks taken on the anterior wall, left atrial appendage (LAA) or the coronary sinus (CS) resulted in a larger registration error (9.1 ± 2.5). The mean error for surface registration was 2.17 ± 1.65. However, surface registration resulted in shifting of the initially registered landmark points leading to a larger error (from 5.6 ± 3.2 to 9.2 ± 2.1; 95% CI 4.2–3.05). Conclusion: Posterior wall landmarks at the PV-LA junction are the most accurate landmarks for image integration in respect to the target ablation area. The concurrent use of the present surface registration algorithm may result in shifting of the initial landmarks with loss of their initial correlation with the area of interest.

Although cardiac resynchronization therapy (CRT) has clearly demonstrated its clinical benefit in patients with congestive heart failure (CHF) and intraventricular conduction abnormalities, selection of eligible patients and/or optimal pacing site are still a matter of debate. The aim of the study was to analyze the spectrum of conduction abnormalities in CRT candidates. A total of 26 patients (mean age 62 +/- 9 years) with CHF and conduction disturbances (QRS > or = 130 ms) were studied. The underlying heart disease was dilated cardiomyopathy (DCM) (n = 12) or coronary artery disease (CAD) (n = 14). High density, left ventricular endocardial activation maps were constructed using an electroanatomic mapping system (CARTO). Based on endocardial activation patterns, left ventricular conduction abnormalities were classified as left bundle branch block (LBBB) (n = 9), nonspecific intraventricular conduction disturbances (n = 10), and the bifascicular block (n = 7). In DCM patients the endocardial activation sequences corresponded with a 12-lead ECG pattern with a homogeneous spread of activation wavefront and the latest activation laterally (LBBB) or anteriorly (bifascicular block), respectively. CAD patients presented with variable activation patterns that reflected the location of the postinfarct scar, and the 12-lead ECG was less predictive. Although there was a trend for longer QRS durations for DCM subjects (170 +/- 23 vs 156 +/- 23 ms, P = NS), left ventricular activation time was significantly longer in the CAD group (115 +/- 21 ms vs 134 +/- 23 ms, P < 0.05). CRT candidates represent a broad spectrum of conduction abnormality patterns with variable inter- and intraventricular activation delays. CAD subjects have more pronounced intraventricular conduction abnormality. The standard ECG is less reliable in the characterization of complex conduction abnormalities.

The goal of this study was to analyze total procedural and fluoroscopic time during initial experience with implantation of LV lead in a single center, and to assess the performance of electrophysiologically-guided approach for cannulation of the coronary sinus (CS) in a subsequent period. Over an initial period of 29 months, a total of 46 attempts to implant biventricular pacing system were revised. During the first phase, only one type of LV electrode was available for three implanters (11 attempts). The second phase covered their early experience with other stylet-controlled LV leads (10 attempts). Additional LV leads including the over-the-wire design were available in the third phase and 25 attempts were done by he most experienced implanter. In a period of advanced experience, 92 implant procedures performed by four implanters using an electrophysiologically-guided approach to CS cannulation were revised. In the first period, success rates for different phases reached 70%, 90%, and 96%, respectively. Significant decrease in both procedural and fluoroscopic times was achieved with increased experience (Phase I: 247.1 +/- 104.5 minutes and 31.2 +/- 34.3 minutes, Phase II: 219.4 +/- 85.6 minutes, and 22.9 +/- 19.1 minutes, Phase III: 116.4 +/- 89.9 minutes and 6.6 +/- 4.4 minutes, respectively, P < 0.05). Advanced experience with electrophysiologically-guided approach to CS cannulation allowed achievement of this target within a reasonable amount of time (15.4 +/- 16.3 minutes) and with minimum fluoroscopic time (2.1 +/- 2.9 minutes). In conclusion, both individual learning curve and technical advances significantly influence success rate, procedural, and fluoroscopic times for biventricular system implantation. Electrophysiologically-guided approach makes cannulation of the CS a highly reproducible procedure that requires minimum fluoroscopic time.

PEICHL, P.,et al.:Clinical Application of Electroanatomical Mapping in the Characterization of “Incisional” Atrial Tachycardias.Scar tissue after surgical procedures for congenital heart disease may create a complex arrhythmogenic substrate and expose patients to the risk of “incisional” tachycardia. We report the usefulness of electroanatomical mapping in the characterization of reentrant circuits and identification of sites of successful radiofrequency (RF) ablation. Methods: Electroanatomical mapping was used to draw activation maps of the right atrium in 6 men and 4 women (mean age45 ± 13.7 years) with 21 atrial tachycardias after corrections of atrial septal defects (n = 6) or tetralogy of Fallot (n = 4). The critical isthmus of reentrant circuits was ablated by RF energy. Results: Macroreentrant circuits were localized on the posterolateral wall of the right atrium in all cases. Scar tissue in that region often contained several pathways that allowed induction of different tachycardias. Interruption of all slow conducting pathways successfully abolished all inducible tachycardias. The cavotricuspid isthmus participated in a figure-of-eight reentrant circuit or in a typical flutter circuit in 6 patients. RF ablation was successful in all but one patient, without significant complications. Conclusion: Electroanatomical mapping allows the precise description of macroreentrant circuits and the identification of all slow conducting pathways. It is a powerful tool for the planning of ablation lines, navigation of ablation catheter, and verification of conduction block. (PACE 2003; 26[Pt. II]:420–425)

Optimum strategy for radiofrequency (RF) catheter ablation of ventricular tachycardia (VT) after inferior wall myocardial infarction (MI) that originates from the posteroseptal process of the left ventricle is not known. We describe a case report of a 57-year-old man who developed recurrent post-MI VT with ECG morphology consistent with this type of VT (i.e., left bundle branch block pattern with predominant R waves from V2 to V6 and left-axis deviation). Endocardial mapping and entrainment during VT demonstrated a critical isthmus of the reentrant circuit in the proximal coronary sinus. RF application terminated VT and rendered it noninducible.